main_java_com_example_harsh_freechat_ChatActivity.java

package com.example.harsh.freechat;

import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.text.TextUtils;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.TextView;

import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.ChildEventListener;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.Query;
import com.google.firebase.database.ServerValue;
import com.google.firebase.database.ValueEventListener;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.StorageReference;
import com.google.firebase.storage.UploadTask;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import de.hdodenhof.circleimageview.CircleImageView;

public class ChatActivity extends AppCompatActivity {

    private String mChatUser;
    private Toolbar mChatToolbar;
    private DatabaseReference mRootRef;
    private TextView mTitleView;
    private TextView mLastSeenView;
    private CircleImageView mProfileImage;

    private FirebaseAuth mAuth;
    private String mCurrentUserId;
    private ImageButton mChatAddBtn;
    private ImageButton mChatSendBtn;
    private EditText mChatMessageView;

    private RecyclerView mMessageslist;
    private SwipeRefreshLayout mRefreshLayout;
    private final List<Messages> messagesList = new ArrayList<>();
    private LinearLayoutManager mLinearLayout;
    private MessageAdapter mAdapter;

    private static final int TOTAL_ITEMS_TO_LOAD = 10;
    private int mCurrentPage = 1;
    private int itemPos = 0;
    private static final int GALLERY_PICK = 1;

    // Storage Firebase
    private StorageReference mImageStorage;

    private String mLastKey = "";
    private String mPrevKey = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_chat);


        mChatToolbar = findViewById(R.id.chat_app_bar);


        setSupportActionBar(mChatToolbar);
        ActionBar actionBar = getSupportActionBar();
        actionBar.setDisplayHomeAsUpEnabled(true);
        actionBar.setDisplayShowCustomEnabled(true);

        mRootRef = FirebaseDatabase.getInstance().getReference();
        mAuth = FirebaseAuth.getInstance();
        mCurrentUserId = mAuth.getCurrentUser().getUid();

        mChatUser = getIntent().getStringExtra("user_id");
        String userName = getIntent().getStringExtra("user_name");
        getSupportActionBar().setTitle(userName);
        LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        View action_bar_view = inflater.inflate(R.layout.chat_custom_bar, null);
        actionBar.setCustomView(action_bar_view);

        //----------Custom action bar items-------------


        mTitleView = findViewById(R.id.custom_bar_title);
        mLastSeenView = findViewById(R.id.custom_bar_seen);
        mProfileImage = findViewById(R.id.custom_bar_image);
        mChatAddBtn = findViewById(R.id.chat_add_btn);
        mChatSendBtn = findViewById(R.id.chat_send_btn);
        mChatMessageView = findViewById(R.id.chat_message_view);
        mAdapter = new MessageAdapter(messagesList);
        mMessageslist = findViewById(R.id.messages_list);
        mRefreshLayout = findViewById(R.id.message_swipe_layout);
        mLinearLayout = new LinearLayoutManager(this);
        mMessageslist.setHasFixedSize(true);
        mMessageslist.setLayoutManager(mLinearLayout);
        mMessageslist.setAdapter(mAdapter);

        //--------IMAGE STORAGE-------------
        mImageStorage = FirebaseStorage.getInstance().getReference();

        mRootRef.child("Chat").child(mCurrentUserId).child(mChatUser).child("seen").setValue(true);

        loadMessages();
        mTitleView.setText(userName);
        mRootRef.child("Users").child(mChatUser).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                String online = dataSnapshot.child("online").getValue().toString();
                String image = dataSnapshot.child("image").getValue().toString();

                if (online.equals("true")) {

                    mLastSeenView.setText("Online");
                } else {
                    GetTimeAgo getTimeAgo = new GetTimeAgo();
                    long lastTime = Long.parseLong(online);
                    String lastSeenTime = getTimeAgo.getTimeAgo(lastTime, getApplicationContext());
                    mLastSeenView.setText(lastSeenTime);
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

        mRootRef.child("Chat").child(mCurrentUserId).addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                if (!dataSnapshot.hasChild(mChatUser)) {
                    Map chatAddMap = new HashMap();
                    chatAddMap.put("seen", false);
                    chatAddMap.put("timestamp", ServerValue.TIMESTAMP);

                    Map chatUserMap = new HashMap();
                    chatUserMap.put("Chat/" + mCurrentUserId + "/" + mChatUser, chatAddMap);
                    chatUserMap.put("Chat/" + mChatUser + "/" + mCurrentUserId, chatAddMap);

                    mRootRef.updateChildren(chatUserMap, new DatabaseReference.CompletionListener() {
                        @Override
                        public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                            if (databaseError != null) {
                                Log.d("Chat Log", databaseError.getMessage().toString());
                            }
                        }
                    });
                }
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {


            }
        });


        mChatSendBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                sendMessage();
            }
        });

        mChatAddBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                Intent galleryIntent = new Intent();
                galleryIntent.setType("image/*");
                galleryIntent.setAction(Intent.ACTION_GET_CONTENT);

                startActivityForResult(Intent.createChooser(galleryIntent, "SELECT IMAGE"), GALLERY_PICK);

            }
        });


        mRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
            @Override
            public void onRefresh() {

                mCurrentPage++;
                itemPos = 0;
                loadMoreMessages();
            }
        });
    }
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == GALLERY_PICK && resultCode == RESULT_OK) {

            Uri imageUri = data.getData();

            final String current_user_ref = "messages/" + mCurrentUserId + "/" + mChatUser;
            final String chat_user_ref = "messages/" + mChatUser + "/" + mCurrentUserId;

            DatabaseReference user_message_push = mRootRef.child("messages")
                    .child(mCurrentUserId).child(mChatUser).push();

            final String push_id = user_message_push.getKey();


            StorageReference filepath = mImageStorage.child("message_images").child(push_id + ".jpg");

            filepath.putFile(imageUri).addOnCompleteListener(new OnCompleteListener<UploadTask.TaskSnapshot>() {
                @Override
                public void onComplete( Task<UploadTask.TaskSnapshot> task) {

                    if (task.isSuccessful()) {

                        String download_url = task.getResult().getDownloadUrl().toString();


                        Map messageMap = new HashMap();
                        messageMap.put("message", download_url);
                        messageMap.put("seen", false);
                        messageMap.put("type", "image");
                        messageMap.put("time", ServerValue.TIMESTAMP);
                        messageMap.put("from", mCurrentUserId);

                        Map messageUserMap = new HashMap();
                        messageUserMap.put(current_user_ref + "/" + push_id, messageMap);
                        messageUserMap.put(chat_user_ref + "/" + push_id, messageMap);

                        mChatMessageView.setText("");

                        mRootRef.updateChildren(messageUserMap, new DatabaseReference.CompletionListener() {
                            @Override
                            public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                                if (databaseError != null) {

                                    Log.d("CHAT_LOG", databaseError.getMessage().toString());

                                }

                            }
                        });


                    }

                }
            });

        }

    }



    private void loadMoreMessages() {
        DatabaseReference messageRef = mRootRef.child("messages").child(mCurrentUserId).child(mChatUser);
        Query messageQuery = messageRef.orderByKey().endAt(mLastKey).limitToLast(10);
        messageQuery.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {

                Messages message = dataSnapshot.getValue(Messages.class);
                String messageKey = dataSnapshot.getKey();
                if(!mPrevKey.equals(messageKey)){
                    messagesList.add(itemPos++, message);

                }else {
                    mPrevKey = mLastKey;
                }


                if(itemPos == 1) {
                    mLastKey = messageKey;
                }

                Log.d("TOTALKEYS", "Last Key : " + mLastKey + " | Prev Key : " + mPrevKey + " | Message Key : " + messageKey);
                mAdapter.notifyDataSetChanged();
                mRefreshLayout.setRefreshing(false);
                mLinearLayout.scrollToPositionWithOffset(10, 0);
            }




            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }

    private void loadMessages() {

        DatabaseReference messageRef=mRootRef.child("messages").child(mCurrentUserId).child(mChatUser);
        Query messageQuery=messageRef.limitToLast(mCurrentPage*TOTAL_ITEMS_TO_LOAD);

        messageQuery.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {

                Messages message=dataSnapshot.getValue(Messages.class);
                itemPos++;
                if(itemPos == 1){
                    String messageKey = dataSnapshot.getKey();
                    mLastKey = messageKey;
                    mPrevKey = messageKey;

                }

                messagesList.add(message);
                mAdapter.notifyDataSetChanged();
                mMessageslist.scrollToPosition(messagesList.size()-1);
                mRefreshLayout.setRefreshing(false);
            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });
    }

    private void sendMessage() {

        String message=mChatMessageView.getText().toString();
        if(!TextUtils.isEmpty(message)){

            String current_user_ref="messages/" + mCurrentUserId + "/" + mChatUser;
            String chat_user_ref="messages/" + mChatUser + "/" + mCurrentUserId;

            DatabaseReference user_message_push=mRootRef.child("messages")
                    .child(mCurrentUserId).child(mChatUser).push();

            String push_id=user_message_push.getKey();

            Map messageMap=new HashMap();
            messageMap.put("message",message);
            messageMap.put("seen",false);
            messageMap.put("type","text");
            messageMap.put("time",ServerValue.TIMESTAMP);
            messageMap.put("from",mCurrentUserId);

            Map messageUserMap=new HashMap();
            messageUserMap.put(current_user_ref + "/" + push_id,messageMap);
            messageUserMap.put(chat_user_ref + "/" + push_id,messageMap);
            mChatMessageView.setText("");
            mRootRef.child("Chat").child(mCurrentUserId).child(mChatUser).child("seen").setValue(true);
            mRootRef.child("Chat").child(mCurrentUserId).child(mChatUser).child("timestamp").setValue(ServerValue.TIMESTAMP);

            mRootRef.child("Chat").child(mChatUser).child(mCurrentUserId).child("seen").setValue(false);
            mRootRef.child("Chat").child(mChatUser).child(mCurrentUserId).child("timestamp").setValue(ServerValue.TIMESTAMP);

            mRootRef.updateChildren(messageUserMap, new DatabaseReference.CompletionListener() {
                @Override
                public void onComplete(DatabaseError databaseError, DatabaseReference databaseReference) {

                    if(databaseError!=null){
                        Log.d("Chat Log",databaseError.getMessage().toString());
                    }

                }
            });
        }
    }
}